Volatile fluorinated β-ketoimines and associated metal complexes

ABSTRACT

Fluorinated β-ketoimine ligands and highly volatile β-ketoiminato metal complexes of the ligands are synthesized by silylating a fluorinated β-diketone to form a silylenolether, and subsequently reacting the silylenolether with a primary amine to form the desired ligand having the structural formula: ##STR1## wherein R 1  and R 2  are independently linear or branched perfluorinated, C 1  -C 8  alkyl groups and R 3  is a phenyl or C 1  -C 8  alkyl, hydroxyalkyl, or ether group, all of which can be partially or fully fluorinated. The corresponding metal complex is formed by treating the ligand with a metal halide.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of co-pending applicationSer. No. 07/270,719, filed Nov. 14, 1988, now U.S. Pat. No. 4,950,790.

TECHNICAL FIELD

The present invention relates to fluorinated organic ligands andvolatile metal complexes formed from such ligands.

BACKGROUND OF THE INVENTION

In the electronics industry there is a growing need for volatile sourcesof different metals to be used in the chemical vapor deposition (CVD) ofmetallic films, metal oxide films, metal silicide films, and the like.The key property required for such metal sources is that they readilyevaporate or sublime to give a metal containing vapor or gas which canbe decomposed in a controlled manner to deposit a film onto a targetsubstrate. Examples of such materials which are commonly utilized in themicroelectronics industry in the preparation of printed circuits andsemiconductor devices include the complex H₃ SiCo(CO)₄ complex which ispyrolyzed in the gas phase at 670°-770° K. to produce CoSi anddimethylzinc (1,4 dioxane) which is reacted with hydrogen selenide at250°-550° C. to produce ZnSe. References teaching the above CVD methodsare B.J. Aylett, et al in Vacuum, 35 p 435-439(1985) and P.J. Hright, etal., in a paper accepted for publication in J. of Crystal Growth, London(1986), respectively.

Known fluorinated metal complexes that are chemically stable and easilyvolatized into the gas phase are the perfluorinated β-diketone metalcoordination compounds along with their parent β-diketone precursorligands, represented by the formulas: ##STR2## wherein R₁ is alkyl orfluoroalkyl, R₂ is fluoroalkyl, and M is a metal capable of forming acoordination compound. The volatility and gas phase stability of thesecompounds have been exploited for the gas chromatographic separation ofvarious metals, the purification of uranium and the manufacture ofspecialty glasses. Decomposing such metal complexes by reaction withhydrogen in the gas phase to deposit thin metal films is taught in U.S.Pat. No. 3,356,527.

In the past, attempts have been made to condense primary amines orprimary diamines with ligands similar to those having the abovestructure. In instances in which R₁ and R₂ are not both fluorocarbongroups, it was reported that an O atom could be replaced with a N atomfrom an amine by direct Schiff-base condensation between an appropriateβ-diketone and an amine. Additionally, the corresponding metal complexcould be synthesized by chelation to a metal ion. See A.E. Martell, etal J. Inorg. Chem. Vol. 5 pp 170-181 (1958).

Sievers, et al. reported in J. Inorg. Nucl. Chem. Vol 32 pp 1895-1906(1970), that ligands in which R₁ and R₂ are both perfluoralkyl and inwhich an oxygen has been replaced with an amine have not beenobtainable. It is believed that such methods have been unsuccessfulbecause the perfluorinated β-diketones are of such high acidity that theamine used the reaction becomes protonated. thereby forming a saltbetween the amine and the β-diketone rather than forming the desiredligand. Sievers, et al do report synthesizing a ligand having thestructure: ##STR3## wherein R₁ =R₂ =CF₃ and R₃ =--CH₂ CH₂ --. Thisligand was reportedly synthesized by sublimation of the salt [(CF₃C(O)CHC(O)CF₃)]₂ ⁻ [NH₃ --CH₂ CH₂ --NH₃ ]⁺². The ligand was reported tobe chemically unstable and hence impossible to isolate.

In U.S. Pat. No. 4,654,053 Sievers. et al. teach a process forseparating gaseous oxygen from a multi-component gas stream using a widerange of Schiff base metal chelates, including those containingperfluoro moieties. No special synthesis techniques are taught, however,for making the perfluoro compounds.

Charles, U.S. Pat. No. 3,594,216 discloses a process for depositing ametallic coating on a substrate by heating the substrate and contactingit with vaporized metal-organic beta-ketoamine chelates. Themetal-organic beta-ketoamines were prepared by conventional synthesistechniques. While a wide range of metal chelates are disclosedgenerally, none of the examples or synthesis techniques specifically useperfluorinated metal chelates.

Johnson, et al in Journal of Fluorine Chemistry, 27 pp 371-378 (1985)reported synthesizing a ligand in which R₁ and R₂ are perfluoroalkyl andoxygen was replaced with an ammonia nitrogen. The Cu⁺² complex was alsoprepared and was reported to be volatile.

BRIEF SUMMARY OF THE INVENTION

The present invention is a class of novel, β-ketoimine ligands andhighly volatile metal complexes of the ligands and also a process formaking the same. The β-ketoimine ligands of the present invention arethose of the general structural formula: ##STR4## wherein R₁ and R₂ areindependently linear or branched, perfluorinated, C₁ -C₈ alkyl groups,and R₃ is any suitable organic functionality such as a phenyl or C₁ -C₈alkyl, hydroxyalkyl or ether group, all of which can be partially orfully fluorinated.

The highly volatile β-ketoiminato metal complexes which are synthesizedfrom these ligands have the structural formula: ##STR5## wherein R₁, R₂and R₃ are as described above, and M is a metal, and n is 1, 2 or 3.

The present invention is also a process for making both the β-ketoimineligands and metal complexes described above. The ligands are synthesizedby silylating a fluorinated B-diketone to form a silylenolether, andsubsequently reacting the silylenolether with a primary amine to formthe desired ligand. The corresponding metal complex is formed bytreating the resulting ligand with potassium methoxide followed bytreatment with a halide salt of the desired metal.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is a class of heavily fluorinated β-ketoimineligands and thermally volatilizable B-ketoiminato metal complexes of theligands. The ligands are characterized in that they are highlyfluorinated and contain oxygen and nitrogen donor atoms which can becovalently coordinated to a central metal atom to form the correspondingmetal complex. This class of ligand. as well as the corresponding metalcomplex, are chemically stable and easily volatized into the gas phase.The high fluorine content of the complex is believed to reduce the Vander Waals forces between individual molecules and hence lower theboiling or sublimination point of the compound.

The heavily fluorinated β-ketoimine ligands of the present invention canbe represented by the structural formula: ##STR6## wherein R₁ and R₂ areindependently linear or branched, perfluorinated. C₁ -C₈ alkyl groups,and R₃ is any suitable organic functionality for example, a phenyl or C₁-C₈ alkyl, hydroxylalkyl or ether group, all of which can be partiallyor fully fluorinated.

The highly volatile metal complexes which are synthesized from theseligands can be represented by the structural formula: ##STR7## whereinR₁, R₂ and R₃ are as described above, and M is a metal and n=1, 2 or 3.These volatile complexes hold great potential for use as metal sourcesin Chemical Vapor Deposition (CVD) processes engaged in the art ofdepositing, for instance, metal films or metal oxide films.

The ligands of structure I above are synthesized by treating afluorinated β-diketone of the formula R₁ COCH₂ COR₂ with potassiumhydride under anhydrous conditions to produce a compound of the formulaR₁ COCHCOR₂ ⁻ K⁺ and subsequently reacting the resultant R₁ COCHCOR₂ ⁻K⁺ with a silylchloride such as, t-butyldimethylsilylchloride. toproduce a silylenolether having the general formula: ##STR8## wherein R₁and R₂ are as described above, and each R₅ is an alkyl group. Thesilylenolether described above is then treated with a primary monoamine,R₃ NH₂ wherein R₃ is as above to produce the desired β-ketoimine ligandof structural formula I; i.e. R₁ COCH₂ CN(R₃)R₂.

To form the metal complex of the β-ketoimine ligand formed above, theligand is initially treated with potassium methoxide to produce acompound of the formula R₁ COCHCN(R₃)R₂ ⁻ K⁺, which is subsequentlytreated with a metal halide of the formula M^(+n) (X)_(n), where n=1, 2or 3, and X is a halogen, to form the desired highly fluorinatedβ-ketoiminato complex of formula II above.

The ligands of formula I produced in accordance with this invention canexist in two tautomeric forms, enol and keto, with the keto form beingrepresented generally by formula I. Preferred ligands and metalcomplexes of the present invention include: ##STR9##

Experimental

In the following examples, temperatures are set forth uncorrected indegrees Celsius. Unless otherwise indicated, all parts and percentagesare by weight.

1,1,1,5,5,5 hexafluoro-2,4-pentanedione, t-butyldimethylsilylchloride,potassium hydride, 2,2,2-trifluoroethylamine, ethylenediamine,ethanolamine, 1,3-propanediamine, 1,3-diamino-2-propanol and analinewere obtained from Aldrich Chemical Co. (940 West St. Paul Ave.Milwaukee, Wis. 53233). 1,1,1,2,2,6,6,6-octafluoro-3,5-hexanedione and1,1,1,2,2,3,3,7,7,7-decafluoro-4,6-heptanedione were obtained fromFairfield Chemical Company Inc. (P.O. Box 20, Blythewood, S.C. 29016).

Solvents used are HPLC grade. Tetrahydrofuran (THF) was distilled fromcalcium hydride under nitrogen, methanol was distilled from Mg metalunder nitrogen. All operations in the preparation of the free ligands orcorresponding complexes are carried out using Standard Schlenk linetechniques described by D.F. Shriver, "The Manipulation of Air SensitiveCompounds" McGraw-Hill Publishing Co.

Microanalyses were performed by Schwarzkopf Microanalytical Laboratory,Woodside, N.Y. or Research Services, Air Products and Chemicals, Inc.'H, ¹⁹ F and ¹³ C spectra were recorded using an IBM SY-200 and a BrukerWH-200 NMR spectrometer.

The chemical structure, along with both the IUPAC and abbreviated namesof the ligands synthesized in the following examples are set out below.The corresponding metal complexes have the similar structure with an (H)being replaced by the metal (see formula II above) . The charge on themetal complex must remain neutral, i.e., if the ligand is diprotonatedone divalent metal atom such as Cu⁺² is required. ##STR10##

EXAMPLE 1 Synthesis of the Silylenolethers of Perfluorinated β-diketones

The following represents a generic synthesis for the preparation of:

(i) 4-(t-butyldimethylsiloxy)-1,1,1,5,5,5-hexafluoro-3-penten-2-one from1,1,1,5,5,5-hexafluoro-2,4-pentanediane.

(ii) 4-(t-butyldimethylsiloxy)-1,1,1,5,5,6,6,6 octafluoro-3-hexen-2-one(and its isomer2-(t-butyldimethylisiloxy)-1,1,1,5,5,6,6,6-octafluoro-2-hexen-4-one)from 1,1,1,5,5,6,6,6-octafluoro-2,4-hexane dione.

(iii)4-(t-butyldimethylsiloxy)-1,1,1,5,5,6,6,7,7,7-decafluoro-3-hepten-2one(and its isomer2-(t-butyldimethylsiloxy)-1,1,1,5,5,6,6,7,7,7-decafluoro-2-hepten-4-one)from 1,1,1,5,5,6,6,7,7,7-decafluoro-2-hepten-4-one.

Potassium hydride (20.0 g, 0.5 moles) is charged into a solid additionfunnel which is fitted to a 1.01 reaction flask; the latter is alsofitted with a rubber septum, an inlet for nitrogen, and a magnetic stirbar. Under an atmosphere of dry nitrogen THF (500 ml) is added to theflask which is subsequently cooled to -78° C. The perfluoro β-diketone(0.5 moles) is then added by syringe to the stirred THF at approx. 0.5ml/min while also slowly adding potassium hydride at such a rate that itis consumed without an excess accumulating in the reaction flask. Afteradding all the reagents, the reaction is left to stir at roomtemperature until all traces of hydride are digested (up to 18 hrs) . Areflux condenser and an addition funnel charged witht-butyldimethylsilylchloride (75.36 g. 0.5 moles) are fitted to thereaction flask, 150 ml THF is run into the addition funnel to dissolvethe silylchloride. This solution is added dropwise over 30 mins to thestirring reaction mixture after which it is refluxed for 18 hrs. Duringthis time a thick white precipitate of potassium chloride forms. Themixture was then filtered under nitrogen to give a pale brown or yellowfiltrate. Approximately 500 ml of THF was then distilled off undernitrogen and the resulting concentrated silylenol ether solution left tocool, thereby precipitating further potassium chloride. This solutionwas then filtered as before then flash vacuum distilled at ˜70 torr toessentially strip all liquids from residual potassium choride. The paleyellow distillat was then redistilled under nitrogen to give thesilylenolether as a moisture sensitive pale yellow liquid.

Each batch of silylenolether collected by distillation showed one majorpeak >90% purity by gas chromatography. A retention time of 6-7 mins wasobserved for this peak when using a Supelco® SPB5 column (30 meter, ID0.53 mm, 0.25μ film) using a helium flow of 4 ml/min and programmed ithan initial temperature of 50° C. for 5 min floowed by heating at 20°C./min to 200° C. and holding at 200° C. for 5 mins. It is noted thatfor the silylenolethers that were dstilled over as one fraction composedof two isomers, the gas chromatography conditions described above didnot resolve each isomer and so the peak that was observed appeared as ifit were of only one component. See Table 1 for analytical data.

                                      TABLE 1    __________________________________________________________________________    Yields and Analytical Data for Silylenol Ethers                                     Isolated                                          Boiling    Starting β-Diketone                 Silylenol Ether Formed                                     Yield                                          Point NMR    __________________________________________________________________________    1,1,1,5,5,5-hexafluoro-                 4-(t-butyldimethylsiloxy)-1,1,1,5,5,5-                                     64%  165-175° C.                                                'H CDCl.sub.3 δ0.32(S,                                                .sub.----6H); δ0.99(S,                                                .sub.----9H);    2,4-pentane dione                 hexafluoro-3-penten-2-one      δ6.27(S, .sub.----1H)                                                .sup.13 C CDCl.sub.3                                                δ-4.34(S, .sub.----2C);                                                δ19.20(S, .sub.----1C)                                                δ25.51(S,3C);                                                δ99.33(S, .sub.----1C)                                                δ116.0(Q, .sub.----1C);                                                δ120(Q, .sub.----1C);                                                δ156.1                                                (Q, .sub.----1C);                                                δ178(Q,1C)                                                .sup.19 F CDCl.sub.3 δ-7                                                6.5(S,3 .sub.--F);-70.2(S,3F)                                                .    1,1,1,5,5,6,6,6-octafluoro-                 4-(t-butyldimethylsiloxy)-1,1,1,5,5,6,6,6-                                     62%, 165-175° C.                                                'H CD.sub.2 Cl.sub.2                                                δ0.35(S, .sub.----9H);                                                δ1.0(S, .sub.----6H);    2,4-pentanedione                 octafluoro-3-hexen-2-one       δ6.4(S,1H)                                                (only major isomer shown)                 and                 2-(t-butyldimethylsiloxy)-1,1,1,5,5,6,6,6-                 octafluoro-2-hexen-4-one                 (ie. two isomers)    1,1,1,5,5,6,6,7,7,7-deca                 4-(t-butyldimethylsiloxy)-1,1,1,5,5,6,6,                                     49%, 169-180° C.                                                'H CD.sub.2 Cl.sub.2                                                δ0.35(S, .sub.----9H);                                                δ1.0(S, .sub.----6H);    fluoro-2,4-pentanedione                 7,7,7-decafluoro-3-hepten-2-one                                                δ6.4(S, .sub.----1H)                                                (only major isomer shown)                 and                 2-(t-butyldimethylsiloxy)-1,1,1,5,5,6,6,                 7,7,7-2-hepten-4-one                 (i.e., two isomers)    __________________________________________________________________________

EXAMPLE 2 Preparation of Solid Cu⁺² (NONA-F[TFEA]₂, Cu⁺²(UNDECA-F[TFEA])₂. Cu⁺² (TRIDECA-F[TFEA])₂

The above metal complexes are obtained by reaction between1,1,1-trifluoroethylamine and the silylenolethers of the perfluorinatedβ-diketones synthesized in Example 1, followed by treatment with copperbromide.

Under a nitrogen atmosphere, 1,1,1-trifluoroethylamine (12.4 ml, 0.16moles) is added over 5 mins to 0.16 moles of neat silylenol ether cooledto -78° C. This mixture is allowed to warm to room temperature andstirred for 1 hr then poured into 400 ml of methanol containing 0.16moles of potassium methoxide and stirred for 10 minutes. To this brightyellow solution, copper bromide (17.1 g, 0.08 moles) is added and themixture stirred fOr 1 hour. The potassium bromide precipitate isfiltered off, solvent stripped away and the resultant solid twicesublimed under dynamic vacuum to give dark green needles of productcomplex. The yields and analytical data are reported in Table 2 below.

                                      TABLE 2    __________________________________________________________________________    Yields and Analytical Data for Cu.sup.+2 (NONA-F[TFEA]).sub.2, Cu.sup.+2    (UNDECA-F[TFEA]).sub.2, Cu.sup.+2 (TRIDECA-F[TFEA]).sub.2                                       Yield                                       Isolated                                            Melting    Starting Enolether  Complex        Solid                                            Point                                                 Mass Spec                                                         Elemental    __________________________________________________________________________                                                         Analysis     ##STR11##          Cu.sup.+2 (NONA-F[TFEA]).sub.2                                       71%  82-86° C.                                                 cal638.9438 found                                                         Cal %: C 26.28; H                                                         0.95; N 4.38; O                                                         5.00; F 53.46; Cu                                                         9.93 Found %: C                                                         26.12; H 0.78; N                                                         3.81; O F 50.40; Cu                                                         10.10     ##STR12##          Cu.sup.+2 (UNDECA-F[TFEA]).sub.2                                       77%  73-75° C.                                                 cal738.9374 found                                                         Cal %: C 25.98; H                                                         0.82; N 3.79; O                                                         4.33; F 56.50; Cu                                                         8.59 Found %: C                                                         25.53; H 0.66; N                                                         3.95; O F 54.60; Cu                                                         8.56     ##STR13##          Cu.sup.+2 (TRIDECA-F[TFEA]).sub.2                                       63%  70-73° C.                                                 cal838.9310 found                                                         Cal %: C 26.97; H                                                         0.75; N 3.49; O                                                         3.99; F 56.87; Cu                                                         7.93 Found %: C                                                         25.57; H 0.55; N                                                         3.49; O F 55.30; Cu                                                         7.47    __________________________________________________________________________

EXAMPLE 3 Preparation of Ligands (H)NONA-F[TFEA], (H)UNDECA-F[TFEA],(H)TRIDECA-F[TFEA]

A saturated solution of the appropriate parent copper complex (fromexample 2) in diethyl ether is prepared and washed with excess 50/50concentrated HCl/H₂ O. The ether layer is then extracted and treatedwith more acid until it holds no further green color. The organic layeris then washed with brine, dried over anhydrous sodium sulfate anddistilled. Yields of 80-90% of isolated pure colorless ligand wererealized. Analytical data is reported in Table 3 below.

                                      TABLE 3    __________________________________________________________________________    Analytical Data for Ligands (H)NONA-F[TFEA]; (H)UNDECA-F[TFEA];    (H)TRIDECA-F[TFEA]    Starting Cu.sup.+2 Complex                   Free Ligand  Elemental Analysis                                                 NMR    __________________________________________________________________________    Cu.sup.+2 (NONA-F[TFEA].sub.2                   (H)NONA-F[TFEA]                                Cal %: C 29.07; H 1.39; N 4.85;                                                 'H CD.sub.2 Cl.sub.2                                                 δ4.07(p, .sub.----2H);                                                 δ6.02(S, .sub.----1H);                                                 2                                O 5.53; F 59.15  δ10.35(bs, .sub.----1H)                                Found %: C 29.41; H 1.41; N                                                 .sup.19 F CDCl.sub.3                                                 δ-78.2(S);                                                 δ-73.2(m);                                O; F 51.70       δ-66.7(m)                                                 .sup.13 C CDCl.sub.3                                                 δ46.5(Q);                                                 δ89.0(S);                                                 δ116.1                                                 (Q); δ118.2(Q);                                                 δ122.5(Q);                                                 δ133(Q);                                                 δ181.4(Q)    Cu.sup.+2 (UNDECA-F[TFEA]).sub.2                   (H)UNDECA-F[TFEA]                                Cal %: C 28.34; H 1.19; N 4.13;                                                 'H CDCl.sub.3 δ4.0(p,                                                 .sub.----2H); δ6.05(S,                                                 .sub.----1H);                                O 4.72; F 61.63  δ10.50(bs,  .sub.----1H                                                 )                                Found %: C 27.76; H 1.04; N                                                 .sup.19 F CDCl.sub.3                                                 δ-124(S);                                                 δ-83.8(S);                                O; F 58.0        δ-74.2(m);                                                 δ-67.6(S)                                                 .sup.13 C CDCl.sub.3                                                 δ11.2(Q);                                                 δ89.7(S):δ107.5                                                 (t); δ118.25(Qt);                                                 δ119.0(Q);                                                 δ123(Q);                                                 δ153.3(Q);                                                 δ183.3(t)    Cu.sup.+2 (TRIDECA-F[TFEA]).sub.2                   ((H)TRIDECA-F[TFEA])                                Cal %: C 27.78; H 1.04; N 3.60;                                                 'H CDCl.sub.3                                                 δ4.0(hp);                                                 δ6.0(S);                                                 δ10.5(bs)                                O 4.11; F 63.47  .sup.19 F CDCl.sub.3                                                 δ-127.8(S);                                                 δ-122.5(m);                                Found %: C 28.08; H 0.73; N                                                 δ-81.8(m);                                                 δ74.0(m);                                                 δ-67.3(S)                                O; F 58.0        .sup.13 C CDCl.sub.3                                                 δ46.43(Q);                                                 δ90.12(S);                                                 δ108(t,hx);                                                 δ109.01(tt);                                                 δ117.63(Qt);                                                 δ118.92(Q);                                                 δ122.87(Q);                                                 δ152.9(Q);                                                 δ182.9(t)    __________________________________________________________________________

EXAMPLE 4 Preparation of Ligands (H)HEXA-F[EOA]

Under a cover of nitrogen, a 100 ml reaction flask fitted with a refluxcondenser, addition funnel and magnetic stir bar is charged with thet-butyl dimethylsilylenol ether of hexafluoro-2,4-pentadione (9.66 g,3×10⁻² moles). The addition funnel is charged with elthanolamine (EOA)(1.83 g, 3.0×10⁻² moles) in 5 ml THF and this solution is then addedover 5 mins, with stirring. to the enolether after which the reactionmixture is refluxed 1.5 hrs. The reaction mixture is then poured intoexcess methanolic copper acetate solution, the entire mixture isextracted with methylene chloride (3×100 ml). The combined organicfractions are washed with water (3×100 ml) then dried over anhydroussodium sulfate. Removal of solvent yields a blue oil which ischromatographically purified via a Chromatron® apparatus (HarrisonResearch, 840 Moana Court, Palo Alto, Calif.) using Kieselgel 60 PF₂₅₄,and CH₂ Cl₂ eluant) to yield a blue crystalline solid (i.e. Cu⁺²(HEXA-F[EOA])₂, MPt 232° C.) . This is treated with HCl to yield(H)HEXA-F[EOA] as a colorless oil. Analytical data is reported in Table4 below.

                                      TABLE 4    __________________________________________________________________________    Analytical Data for (H)HEXA-F[EOA]    Starting Enolether                    Alkanolamine                           Ligand Formed                                     NMR    __________________________________________________________________________     ##STR14##      Ethanolamine                           (H)HEXA-F[EOA]                                     .sup.1 H CDCl.sub.3 δ2.22(bs,                                     1H);δ3.62(Q, 2H); δ3.85(t,                                     2H);δ5.83(S,1H); δ10.8(bs,                                     1H) .sup.19 F CDCl.sub.3 δ -                                     77.7(S);δ67.7(S) .sup.13 C                                     CDCl.sub.3 δ46.94(S);δ60.29(S                                     ); δ85.74(S);δ117.0(Q);.delta                                     .119.0(Q); δ154(Q);δ179.5(Q)    __________________________________________________________________________

EXAMPLE 5 Preparation of Ligand (H)HEXA-F[AN]

Under nitrogen, a 50 ml reaction flask fitted with a reflux condenser ischarged with the silylenolether of hexafluoro 2,4-pentanedione (9.66 g,3×10⁻² moles) and aniline (2.79 g, 3×10⁻² moles) added. The nixture wasthen refluxed for 35 mins and distilled under vacuum to yield 8.0 g(H)HEXA-F[AN] at 140° C./10 torr as a yellow liquid.

Yield=94%.

NMR: 'H CDCL₃ δ6.05(S,1H); δ7.25(m,2H); δ7.40(m,3H); δ11.90(bS,1H). ¹⁹ FCDCL₃ δ--77.8(S); δ--64.1(S). ¹³ C neat δ88.0(S); δ117.21(Q);δ119.82(Q); δ126.56(S); δ128.68(S); δ129.45(S); δ136.85(S); δ153.25(Q);δ180.51(Q).

Elemental Analysis: Cal for C₇ H₆ NO₂ F₆ % C 33.61; H 2.42; N 5.60; O12.79; F 45.57. Found: % C 49.31; H 3.68; N 4.15; F 31.0.

EXAMPLE 6 Preparation of a Metal Complex of (H)NONA-F[TFEA]

Under nigrogen, potassium methoxide (1.75 g, 0.025 moles) is dissolvedin 150 ml dry methanol and 0.025 moles of a β-iminoketone ligand isadded. The mixture is then stirred for 15 minutes to give a clear brightyellow solution. Solid metal dibromide (0.025 moles) is then added andthe mixture stirred an additional 1 hour. The mixture is then filtered,the methanol evaporated off from the filtrate and the resultant solideredissolved in toluene (100 ml). This solution is filtered to removeresidual potassium bromide and the filtrate evaporated to a solid thatis then sublimed under a dynamic vacuum to yield the product complex.The analytical data is as follows:

    ______________________________________    Metal Bromide  =     CoBr.sub.2    Complex Formed =     Co.sup.+2 (NONA-F[TFEA]).sub.2    Yield          =     83%    M.P.           =     76-77° C.    ______________________________________

Elemental Analysis: Cal for C₁₄ H₆ N₂ O₂ F₁₈ CO: % C 26.48; H 0.95; N4.41; O 5.04; F 53.84; Co 9.28. Found: % C 25.99; H 0.52; N 4.35; O ; F45.0; Co 9.51.

EXAMPLE 7 Relative Volatility Measurement of Perfluoro β-ketoiminatoComplexes

A standard weight loss experiment for each metal complex was conductedby heating a sample of approximately 50 mg at 10° C./min under a 100cc/min flow of nitrogen using a DuPont Model No. 951. ThermalGravimetric Analyzer in conjunction with a model No. 9900 Controller.Table 5 below indicates that all of the metal complexes tested in thisway are clearly volatile, leaving as little as 0.34% residue at the endof an evaporation cycle. The data reported indicates that theevaporation of these complexes is a smooth process, i.e. a gradual andeven transition from the solid to the gas phase.

                  TABLE 5    ______________________________________    Volatility of Perfluoro β-ketoiminato Copper Complexes                     Temperature T° C.                     at which complex                                   Residual                     is completely weight left    Complex          vaporized     at T° C.    ______________________________________    Cu.sup.+2 (TRIDECA-F[TFEA]).sub.2                     162           0.342%    Cu.sup.+2 (UNDECA-F[TFEA]).sub.2                     157           0.652%    Cu.sup.+2 (NONA-F[TFEA]).sub.2                     150           1.81%    ______________________________________

EXAMPLE 8

A run was carried out to react a fluorinated β-diketone with an amine inan attempt to form a β-ketoimine ligand via published procedures thatare effective for the condensation of unfluorinated β-diketones orpartially fluorinated β-diketones with amines to yield β-ketoiminesligands.

Wallis, et al., (Inorg. Chem. Vol. 13, No. 4. 1974) describe thereaction of 1,1,1-trifluoro-2,4-pentanedione (a partly fluorinatedβ-diketone) with an amine in methanol solvent to yield a β-ketoimineligand. The reagents are simply mixed together at 20° C., gently warmedto 30° C. for 30 minutes and the product precipitated by pouring thereaction mixture into water. Similarly, Rugheimer, L. (Ber. 47, 2759,1914) describes how 2,4-pentanedione (an unfluorinated β-diketone) issuccessfully reacted with triethylamine to yield a β-ketoimine bycooling 2.1 equivalents of the β-diketone to -21° C., adding oneequivalent of the amine, allowing to warm to room temperature thenheating for one hour. The authors also note that this reaction can berun using ethanol as solvent.

The following reaction was run to test the viability of theabove-synthetic approaches for preparing β-ketoimine ligands fromfluorinated β-diketones and amines. Specifically, an attempt was made toprepare a β-ketoimine ligand from1,1,1,5,5,5-hexafluoro-2,4-pentanedione and ethylamine as follows:

Ethylamine (1.3 ml., 0.9 g, 0.02 moles) were dissolved in 10 ml ofabsolute ethanol and cooled to 0° C. 1,1,15,5,5-hexafluoro-2,4-pentanedione (2.82 ml, 4.16 g, 0.02 moles) weredissolved in 10 ml of absolute ethanol and slowly added to theethylamine solution over a period of five minutes with stirring. Afterstirring at 0° C. for fifteen minutes. the solution was allowed to warmto room temperature, then refluxed for one hour. Gas chromatographicanalysis of the resultant reaction mixture indicated one major productidentified as the hexafluoroacetylacetonate salt of ethylamine. Only atrace of the desired ketoimine ligand was found (identified by massspectroscopy) representing less than 0.1% of the reaction mixture; thatis, present in a sufficiently low quantity as to preclude this syntheticroute as being a viable means to prepare this compound.

EXAMPLE 9

A run was carried out in an attempt to reproduce the work of Richardsonand Sievers for the synthesis of the ligand ##STR15## as described inJ.Inoro. Nucl. Chem. 1970. vol. 32, p.1895 to 1906.

4.16 g (0.02 moles) of 1,1,1,5,5,5-hexafluoro-2,4-pentanedione weredissolved in 10 ml of benzene and to this solution 0.60g (0.01 mole) ofethylenediamine dissolved in 10 ml benzene were slowly added, withstirring, over a period of five minutes. A cream colored precipitateslowly formed and heat was evolved. The mixture was then boiled andfiltered hot. The resulting white precipitate was then washed with hotbenzene, refiltered and left to air dry. Yield=4.4 g white solid. Tocheck if any ligand may have formed at this point, the white solid wasanalyzed by Gas Chromatography (using a Hewlett Packard 5880A gaschromatograph). In this determination an acetone solution of the whitesalt was shown to contain none of the desired ligand (by comparison toresults obtained for the analysis of pure authentic ligand; i.e., H₂--DODECA--F[EDA] as obtained via the silylenolether route as describedin this patent disclosure). The white salt was then heated under vacuumin a sublimator to 90° C. whereupon the apparatus was sealed shut andthe sublimation process allowed to occur. The temperature of the coolingwater was set at 16 C. After two hours, a fine powdery film had formedupon the cold finger of the sublimator. This did not bear a strongresemblance to the "large shiny white feathery needles" described byRichardson and Sievers. Gas chromatographic analysis of this solid filmshowed that it contained no H₂ --DODECA--F[EDA] ligand. The cold fingerof the sublimator was then cleaned, the apparatus reassembled and thesublimation process reinitiated under the same conditions as beforeallowing two hours of sublimation time. Again, a white film appeared onthe cold finger. Gas chromatographic analysis of this solid indicated atotal absence of H₂ --DODECA--F[EDA] ligand.

Having thus described the present invention, what is now deemedappropriate for Letters Patent in set out in the following appendedclaims.

What is claimed is:
 1. A thermally volatilizable, β-ketoiminato metalcomplex having the structural formula: ##STR16## wherein R₁ and R₂ areindependently linear or branched, perfluorinated, C₁ -C₈ alkyl groups,R₃ is an unfluorinated, partially fluorinated or fully fluorinatedphenyl or C₁ -C₈ alkyl, hydroxyalkyl or ether group, M is a metal whichis capable of forming a complex with a ligand as shown above, and n=1, 2or
 3. 2. A metal complex in accordance with claim 1 wherein both R₁ andR₂ are CF₃.
 3. A metal complex in accordance with claim 1 wherein R₁ andR₂ are independently perfluorinated methyl, ethyl or propyl groups.
 4. Ametal complex in accordance with claim 3 wherein R₃ is CH₂ CF₃.
 5. Ametal complex in accordance with claim 1 wherein M^(+n) is CU⁺².
 6. Ametal complex in accordance with claim 1 wherein M^(+n) is Co⁺².
 7. Aprocess for making a thermally volatizable, β-ketoiminato metal complexhaving the structural formula: ##STR17## wherein R₁ and R₂ areindependently linear or branched, perfluorinated, C₁ -C₈ alkyl groups,R₃ is an unfluorinated, partially fluorinated or fully fluorinatedphenyl or C₁ -C₈ alkyl, hydroxyalkyl or ether group, M is a metal whichis capable of forming a complex with a ligand as shown above, and n=1, 2or 3, said process comprising:(a) treating a β-diketone of the formulaR₁ COCH₂ COR₂ with potassium hydride under anhydrous conditions toproduce a compound of the formula R₁ COCHCOR₂ ⁻ K⁺ ; (b) treating theresultant R₁ COCHCOR₂ ⁻ K⁺ with a silylchloride of the formula (R₅)₃SiCl, wherein each R₅ is independently an alkyl group, to produce asilylenolether of the formula ##STR18## wherein R₁, R₂ and R₅ are asabove; (c) treating said silylenolether with a primary monoamine of theformula R₃ NH₂ wherein R₃ is as described above to produce the desiredβ-ketoimine ligand; (d) treating the β-ketoimine ligand produced in step(c) with potassium methoxide to produce a comopund of the formula R₁COCHCN(R₃)R₂ ⁻ K⁺ wherein R₁, R₂ and R₃ are as above; and (e)subsequently treating the compound formed in step (d) with a metalhalide of the formula M^(+n) (X)_(n), wherein N=1, 2 or 3 X is ahalogen, to form the desired metal complex.